append.js

/*:nodoc:*
 * class ActionAppend
 *
 * This action stores a list, and appends each argument value to the list.
 * This is useful to allow an option to be specified multiple times.
 * This class inherided from [[Action]]
 *
 **/

'use strict';

var util = require('util');

var Action = require('../action');

// Constants
var $$ = require('../const');

/*:nodoc:*
 * new ActionAppend(options)
 * - options (object): options hash see [[Action.new]]
 *
 * Note: options.nargs should be optional for constants
 * and more then zero for other
 **/
var ActionAppend = module.exports = function ActionAppend(options) {
  options = options || {};
  if (this.nargs <= 0) {
    throw new Error('nargs for append actions must be > 0; if arg ' +
        'strings are not supplying the value to append, ' +
        'the append const action may be more appropriate');
  }
  if (!!this.constant && this.nargs !== $$.OPTIONAL) {
    throw new Error('nargs must be OPTIONAL to supply const');
  }
  Action.call(this, options);
};
util.inherits(ActionAppend, Action);

/*:nodoc:*
 * ActionAppend#call(parser, namespace, values, optionString) -> Void
 * - parser (ArgumentParser): current parser
 * - namespace (Namespace): namespace for output data
 * - values (Array): parsed values
 * - optionString (Array): input option string(not parsed)
 *
 * Call the action. Save result in namespace object
 **/
ActionAppend.prototype.call = function (parser, namespace, values) {
  var items = [].concat(namespace[this.dest] || []); // or _.clone
  items.push(values);
  namespace.set(this.dest, items);
};